This paper is about designing scenarios in Game Based Learning. Indeed, Game Based Learning (GBL) activities are moving to integrate new technologies and new devices, to further facilitate individual and collaborative learning situations, in both virtual and physical environments. In order to aid teachers and content designers in creating new GBL scenarios that take advantage of new multi-device platforms, the need for expressive and simple to use scripting models arises. The use of such models favors sharing, reuse and adaptation of scenarios, for example a scenario created for teaching biology to primary school level students can be adapted to be presented to college students. This process of reusing existing scenarios can accelerate the conception process for teachers and pedagogical content creators. Current models have either limited or no support for scripting multi-device scenarios. Furthermore, many models offer little support for scenarios with multiple environments that change over time (e.g. An activity that starts in a virtual game, which then transitions into an activity that takes place in the classroom). In this paper, we aim to address the issue of creating game based learning scenarios in the context of multi-device and multi-environment situations. To this end, we propose a new model for scripting game based learning scenarios. This model will notably take into account three criteria relating to (1) multi-user and collaborative situations, (2) multi-device support (e.g. using tablets and tactile tabletop surfaces in tandem), and (3) multi-environment scenarios (e.g. designing scenarios mixing virtual game environments and traditional class room situations). Our model describes pedagogical and entertaining activities in a hierarchical manner. An activity can be decomposed into a “flow” which is a sequence of activities. Each activity contained in the flow can also be decomposed. This structure provides a scalable description for scenarios. The idea is that teachers and pedagogical content creators are never required to describe their scenario in full detail, but can do so if they wish. Key features of our model are the expression of different player groups and roles in these groups, the planning of observations and regulation mechanisms during the conception phase, the reusability and adaptability of the created scenarios. This model is tested on two different contexts, a simple one that utilizes tablets and a tactile table-top surface in tandem, and a more complex scenario that uses a virtual game before moving on to tactile table-top surfaces and finishing up with multiple groups and roles using drones and interactive white-boards for presentations. The model is still currently in development using a Participatory Design method where we work with teachers and pedagogical content creators to adapt and adjust the model to better suit their needs in terms of expressivity and ease of use.